docs: Add secrets doc (#4814)

* Add secrets doc

Signed-off-by: Sherlock113 <sherlockxu07@gmail.com>

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---------

Signed-off-by: Sherlock113 <sherlockxu07@gmail.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

docs/source/bentocloud/how-tos/index.rst

@@ -12,6 +12,7 @@ They are recipes, directions to achieve a specific end result, and are wholly **
 * :doc:`call-deployment-endpoints`
 * :doc:`autoscaling`
 * :doc:`manage-access-token`
+* :doc:`manage-secrets`
 * :doc:`manage-users`
 * :doc:`byoc`
 
@@ -24,5 +25,6 @@ They are recipes, directions to achieve a specific end result, and are wholly **
    call-deployment-endpoints
    autoscaling
    manage-access-token
+   manage-secrets
    manage-users
    byoc

docs/source/bentocloud/how-tos/manage-secrets.rst

@@ -0,0 +1,56 @@
+==============
+Manage secrets
+==============
+
+Secrets can store sensitive data like API keys, authentication tokens, and credentials, essential for accessing various services or resources. BentoCloud provides a secure and flexible environment for injecting required secrets into AI model Deployments.
+
+This document explains how to create and use secrets on BentoCloud.
+
+Create a secret
+---------------
+
+1. Navigate to the **Secrets** page and click **Create**.
+2. Choose how to create your secret:
+
+   - **From a template**: Use predefined templates for popular services like OpenAI, AWS, Hugging Face, and GitHub. The templates are designed with common keys required for these services.
+   - **Custom secrets**: Create a secret by defining custom key-value pairs specific to your model's needs.
+
+3. On the setup page, provide the necessary information for the secret:
+
+   .. image:: ../../_static/img/bentocloud/how-to/manage-secrets/create-a-secret-bentocloud.png
+
+   - **Name**: The name of the secret.
+   - **Description**: A description of the secret, detailing its usage.
+   - **Mounted as**:
+
+     - **Environment variables**: The environment variables in the secret are accessible in both the image building and Deployment containers.
+     - **File**: Inject the secret as a read-only file (or multiple files, depending on the number of key-value pairs in this secret). You need to specify the directory path within the container where the secret will be mounted; ensure this path is under the ``$BENTOML_HOME`` directory.
+
+   - **Key**: The name of the secret key.
+   - **Value**: The value of the secret key. If it is mounted as a file, you can optionally specify the sub path where it should be located in the secret path. For example, if the secret path is ``$BENTOML_HOME/demo`` and the sub path is ``secrets/password``, the full path of the secret key will be ``$BENTOML_HOME/demo/secrets/password/<KEY_NAME>``.
+
+4. Click **Add** to add another key-value pair for the secret if necessary.
+5. Click **Save** to store the secret.
+
+Modify a secret
+---------------
+
+1. Click an existing secret on the **Secrets** page.
+2. On the details page, click **Edit** and update your desired field.
+3. Click **Update** to save your change. It is important to note that:
+
+   - You can't modify a secret key's name.
+   - If you change the value of a secret key, you need to restart the Deployment using the secret so that the update can take effect.
+   - If you add a new key-value pair or remove any existing key-value pair from the existing secret, we recommend you recreate the Deployment using the secret.
+
+Use secrets for a Deployment
+----------------------------
+
+1. During the Deployment creation, select the required secret from the **Secrets** dropdown menu.
+2. Attach the desired secret to your Deployment. It will be integrated either as an environment variable or a file, based on the configuration set when the secret was created.
+
+   .. image:: ../../_static/img/bentocloud/how-to/manage-secrets/use-a-secret-for-deployment.png
+
+   .. warning::
+
+      When mounting multiple secrets to a single Deployment, ensure that there are no conflicting key-value pairs across the secrets. For example, different secrets should not contain the same keys with different assigned values.